I'm the same height and ended up doing both modifications to get more legroom. It helped tremendously in my 76. Used some steel straps to extend both the driver's and passengers seats and gained about an inch and a half more room for each.
Doesn't sound like lot but it definitely helps. Not sure I still have any pictures of the installation, it was a few years ago. Really wasn't hard to do, just a few nuts/bolts and 4 straps I bought at Lowes for around
$30 then cutting to fit, precise drilling and bolting back together. Easy weekend project.
Went with a smaller steering wheel when I installed power steering and have had no issues. Definitely don't miss that giant OEM wheel. Used a steering wheel from a hilux truck and the splines matched perfectly, I believe most any non airbag Toyota wheel would work. Not the best picture but you can see the smaller steering wheel here on the 76 steering column. Very easy to swap.
Edit - found this Pic of the passenger side, the straps bolt on to the stock seat bracket then holes are drilled further back and the seat is bolted in as far back as possible. Good luck!!!
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